Aneurysms occur in blood vessels in locations where, due to age, disease or genetic predisposition, insufficient blood vessel strength or resiliency may cause the blood vessel wall to weaken and/or lose its shape as blood flows, resulting in a ballooning or stretching of the blood vessel at the limited strength/resiliency location, thus forming an aneurysmal sac. Left untreated, the blood vessel wall may continue to expand to the point where the remaining strength of the blood vessel wall cannot hold and the blood vessel will fail at the aneurysm location, often with fatal result.
Various implantable medical devices and minimally invasive methods for implantation of these devices have been developed to deliver these medical devices within the vascular system. These devices are advantageously inserted intravascularly, typically from a delivery catheter. In order to prevent rupture of an aneurysm, a stent graft may be introduced into a blood vessel, deployed, and secured in a location within the blood vessel such that the stent graft spans the aneurysmal sac. The outer surface of the stent graft, at its opposed ends, abuts and seals against the interior wall of the blood vessel at a location where the blood vessel wall has not suffered a loss of strength or resiliency. The stent graft channels the blood flow through the hollow interior of the stent graft, thereby reducing, if not eliminating, any stress on the blood vessel wall at the aneurysmal sac location.
In the aorta of a human or animal patient, there are a number of important branch vessels which, when treating an aneurysm through deployment of an endovascular graft, must not be occluded. Current stent graft systems utilize fenestrations or perforations within stent graft walls intended to be aligned with the opening of a given branch vessel, but placement of the stent graft must be very exact and operational alignment is often unsuccessful. When proper fenestration alignment fails, the wall of the deployed stent graft prevents blood flow to the branch vessel. In this case, the physician has no endovascular backup option and must proceed with a significantly more invasive procedure.
Even when the fenestration is properly aligned with the opening of the branch vessel, the fenestration may rotate away from the branch vessel. To prevent this rotation from occurring, a stent graft may be deployed within the branch vessel with one of its ends married to or joined with the fenestration of the previously placed stent graft. The techniques to marry another stent graft to that fenestration are often time consuming, require complicated surgical procedures and demand additional vessel or vascular access points. The marrying of two stent grafts via a fenestration also has the additional problem of an inadequate seal where the two stent grafts are joined.
Further, current common iliac aneurysm treatments involve ligation or embolization of the internal iliac artery, frequently leading to side effects including, but not limited to, erectile dysfunction in men, decreased exercise tolerance, and compromise to pelvic profusion that may result in bowel ischemia and death.